JPS63128097A - Conversion of synthetic gas to aromatic hydrocarbon - Google Patents

Abstract

PURPOSE:To produce a hydrocarbon (gasoline) especially having high octane value, by converting a mixed synthetic gas of CO and H2 to dimethyl ether and contacting the ether with a crystalline silicate catalyst at a high temperature to convert the ether to an aromatic hydrocarbon. CONSTITUTION:A mixed synthetic gas composed of CO and H2 is made to contact with a catalyst consisting of a methanol synthesis catalyst and an acid- type dehydration catalyst at a high temperature of <=400 deg.C and converted to dimethyl ether. The dimethyl ether is dehydrated and converted to an aromatic hydrocarbon by contacting with a crystalline silicate catalyst expressed by formula (R is univalent or bivalent cation; n is atomic valence of R; M is trivalent transition metal ion or Al ion; a+b+c=1, a>=0, b>=0, c>=0, a+b>0; y is >=12) at a high temperature of <=500 deg.C.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to the production of aromatic hydrocarbons, particularly high-octane hydrocarbons (gasoline), from synthesis gas produced from natural gas, heavy oil, coal, etc. Regarding how to.

[Conventional technology]

As a method for producing gasoline from synthesis gas, Fe, C
Fischer using catalysts such as O, Ni, Ru, etc.
The Trobutsch (F-T) method, the IP-T catalyst, the method using a composite catalyst of a methanol synthesis catalyst and a crystalline zeolite catalyst, and the two-step synthesis method using a crystalline zeolite catalyst via methanol, dimethyl ether, etc. be.

The two-step synthesis method is characterized by the catalyst (crystalline zeolite catalyst) used, and Mopil Oil Co., Ltd.
712), and the present applicant has also proposed a method using a transition metal silicate zeolite catalyst (Japanese Patent Application No. 55-8540).
4. Japanese Patent Application No. 57-75454) Q: It has already been proposed.

In any of the proposed methods, for the first stage of synthesis of dimethyl ether, a method using a mixed catalyst of a methanol synthesis catalyst and an acid type dehydration catalyst is usually used.

[Problem that the invention seeks to solve]

The first step of the two-step synthesis method for gasoline synthesis from syngas is the synthesis reaction of dimethyl ether (sco+5z=
Ouma00H1+COs) is a reaction accompanied by large exothermic heat, and if the reaction heat is not properly controlled and the ashes temperature rises, the dimethyl ether conversion rate decreases. Furthermore, if the hydrogen/carbon monoxide ratio of the raw material synthesis gas is small, the reaction rate will decrease, which will also result in a decrease in dimethyl ether conversion in the actual device. In order to increase the gasoline yield from synthesis gas, it is important for K to increase the conversion rate of dimethyl ether as an intermediate product, and in general, the hydrogen/carbon monoxide ratio of raw material synthesis gas is the same as that of coal gas ratio gas. In many cases, the ratio is close to 1 (stoichiometrically it is 1). In order to increase the gasoline yield from such raw material synthesis gas with a low hydrogen/carbon monoxide ratio, it is necessary to increase the dimethyl ether conversion rate. It becomes important.

The present invention responds to the above-mentioned needs by converting gasoline from synthesis gas into two parts.
The object of the present invention is to provide a method that can increase the yield of dimethyl ether in the first stage synthesis reaction of dimethyl ether when it is produced by a stepwise synthesis method.

The present invention is a two-step method for synthesizing liquid hydrocarbons (gasoline) from synthesis gas consisting of a mixture of carbon monoxide and hydrogen via dimethyl ether. hydrogen is separated from the reaction product consisting primarily of dimethyl ether and recycled to the feed synthesis gas, resulting in a hydrogen/carbon monoxide ratio greater than that of the feed synthesis gas. to increase the dimethyl ether conversion of the synthesis gas, and the second step involves converting said dimethyl ether in dehydrated form to the molar ratio of oxides (
1,0±α Lee-, Ao* (aLa, O,-bOe, O
CcM, O, ) 67SiO.

In the above formula, R; one or more monovalent or divalent cations n; valence M of R; one or more pentavalent transition metal ions and/or aluminum ions a+b+c-ml a> Ob〉.

Aroma of synthesis gas characterized in that it is brought into contact with a crystalline silicate catalyst having a chemical composition of C≧O a +b ) O y〉 12 at high temperatures up to 500° C. to produce organic products containing aromatic hydrocarbons. This is a conversion method to group hydrocarbons.

That is, in order to increase the gasoline yield from synthesis gas, the present invention separates unreacted hydrogen gas from the first-stage dimethyl ether synthesis reaction product using a means such as a membrane separator, and uses this for raw material synthesis. By circulating the gas and supplying it to the dimethyl ether synthesis reactor, the hydrogen/carbon monoxide ratio is increased compared to the raw material synthesis gas and the dimethyl ether conversion reaction rate is accelerated, thereby increasing the dimethyl ether conversion rate from the synthesis gas. This is a method to efficiently increase gasoline yield.

One embodiment of the two-step synthesis method for synthesizing gasoline from synthesis gas according to the present invention will be described with reference to the process 70-sheet of FIG.

In FIG. 1, 1 is the first stage dimethyl ether synthesis reactor, and 2 is the second stage gasoline synthesis reaction.

Synthetic gas 101 produced using natural gas, coal, biomass, etc. as a raw material has moisture removed in a gas storage tank 4, and then is pressurized in a gas compressor 11.

The raw material synthesis gas compressed to 20 to 100 ky15+1''G passes through the preheater 9, becomes preheated raw material synthesis gas 102, and is supplied to the dimethyl ether synthesis reactor 1.

The reactor 1 is, for example, a multitubular heat exchanger type reactor, and the reaction tube is filled with a molded composite catalyst consisting of a mixture of a methanol synthesis catalyst and an acid type dehydration catalyst. As the methanol catalyst, Zn-Cu-Or type or Zn-Cu-Al type is used, and as the acid type dehydration catalyst, alumina is used.

Under this composite catalyst, the dimethyl ether synthesis reaction is co+2z ==an, oT1 2C! E, O! E: GocT1sooa, -4-4°c
o + II! o === c o! + H.

It is thought that the reaction proceeds as a sequential reaction with the main reaction as the main reaction.

Therefore, stoichiometrically, the hydrogen/carbon monoxide ratio is approximately 1. It has been experimentally found that this reaction rate increases approximately in proportion to the hydrogen/carbon monoxide ratio.

The reaction temperature is preferably 150°C to 400°C, and the equilibrium reaction conversion rate is higher at lower temperatures. Due to the large amount of reaction heat generated, a fixed bed reactor produces a temperature distribution within the reactor.

The reaction product 103 is cooled by exchanging heat with the supplied synthesis gas 101 in the preheater 9, and then enters the storage tank 5. Here, most of the produced dimethyl ether, by-product methanol, ethanol, and water are condensed, and the non-condensable gas 104, which is mainly composed of unreacted hydrogen, carbon monoxide, and by-product carbon dioxide gas, is introduced into the hydrogen separator 3. Ru.

The hydrogen separator 3 is preferably a membrane separation device such as a polyimide polymer membrane, and the hydrogen gas 10 that has passed through this separation membrane is
5 is pressurized by the compressor 12 and recycled to the feedstock gas 101 as circulating hydrogen 106.

As a result, in the reactor 1, the hydrogen/carbon monoxide ratio is always maintained higher than that of the feed synthesis gas, and as a result, the reaction rate is high, and as will be seen in the examples below, the carbon monoxide conversion rate at the reactor outlet is is higher than that without hydrogen gas circulation, and the dimethyl ether conversion rate is improved. Carbon dioxide gas containing partially uncondensed dimethyl ether from which hydrogen has been separated;
A gas 107 consisting of carbon monoxide, hydrogen, etc. is supplied to the second stage reactor 2 together with the generated dimethyl ether, methanol, etc. 10B.

Furthermore, if equipment for recovering dimethyl ether is installed in the line 107, the gas containing dimethyl ether as a main component can be sent to two stages.

The second stage reactor 2 for synthesizing gasoline from dimethyl ether or the like is, for example, a fluidized bed type reactor filled with a crystalline silicate catalyst. This reactor includes a catalyst supply tank 6
and a catalyst extraction tank 7 are provided so that the catalyst can be supplied and extracted intermittently or continuously. The crystalline silicate catalyst used here is the same as that used in the method previously proposed (Japanese Patent Application No. 57-75454), and is expressed in terms of the molar ratio of oxides in the dehydrated form. (1,0±(LA)RJOs (aLa20.@b(
e, O, * CM, O,) @7SiO.

It has a chemical composition of The reaction product mainly composed of dimethyl ether produced in the first stage has a reaction temperature of 250℃~
500℃, reaction pressure 100kg/eFI&! When it comes into contact with the above catalyst under conditions below G, it is converted into gasoline with a high octane number and a high content of aromatic hydrocarbons.

The second stage reaction product 109 is taken out in gaseous form, cooled in a condenser 10 and enters a high pressure separator 8 . High pressure separator 8
By-product water 110 and non-condensable gases 111 such as carbon dioxide and unreacted gas are separated from the water, and liquid hydrocarbons 112 enter the low-pressure separator 15. Mainly C6-hydrocarbon 11
5 is separated and C-hydrocarbon 114 is taken out as product gasoline.

[Experimental Example 1] A mixed molded catalyst of 1 part of 0u-Zn-Or oxide methanol catalyst and 1 part of r-alumina catalyst was used as a catalyst for the first stage reaction, and a hydrogen/carbon monoxide molar ratio of 1.0 was used. The synthesis gas was heated to a reaction tube wall temperature of 500°C and a reaction pressure of a o H/do.
The conversion reaction to dimethyl ether was carried out under the reaction conditions of a gas hourly space velocity of GHBV-toooh-t (reaction, based on the amount of gas at the tube inlet), and the following intermediate product was obtained.

Conversion rate of carbon monoxide 62.0% Intermediate product composition (mol%) Dimethyl ether 1 z6% carbon oxide
52.4 hydrogen 524
Chi H, O10 Horse OII, 00. ,(!III,
17.6% The dimethyl ether synthesis catalyst used in the first stage reaction was produced as follows.

au(no,), *5zo; 152 y, Z
n(No,), -6zo ;? 19 and Or(Ho
g) 1.9H,O: 1521 was diluted to 500° with water and heated to 90°C. To this was added a 104 NaOH solution preheated to 90°C while stirring until the PR was 12
It was added until. After cooling, the precipitate was filtered through a Puchner PET and washed with pure water until the pH of the washing water became 7.8. Next, the precipitate was dried at 120°C and then at 320°C in air.
It was baked for 3 hours. The obtained composition was OuO-ZnO-
The weight ratio of OrfiO@ was 50:25:25.

A part of the composition was ground into particles of 100 mesh or less, mixed with Condea type 1'ural BB y-alumina powder in a ratio of 50:50 by weight, compression molded into pellets, and then pulverized again at 20 to Grind to a particle size of 52 mesh,
Dimethyl ether synthesis catalyst 51111F was prepared.

[Experimental Example 2] Using the same catalyst and raw material synthesis gas as in Experimental Example 1 for the first stage reaction, hydrogen gas separation from the reaction product shown in Fig. 1) and a reaction apparatus equipped with this circulation system ( The reaction tube was the same as in Experimental Example 1), the hydrogen/-carbon monoxide molar ratio at the inlet of the reaction tube was 2.0, the reaction tube wall temperature was 500°C, and the reaction pressure was 40°C.
hour/iGs gas space velocity GH day v-1,500h-1 (
The conversion reaction of carbon monoxide to dimethyl ether was carried out under the reaction conditions (based on the amount of gas at the inlet of the reaction tube), and the following intermediate product was obtained.

Conversion rate of carbon monoxide 72.9% Intermediate product composition Dimethyl ether 12.0'fa Carbon monoxide 1/4% Hydrogen 62.6/4
o%am, o”a, aO!, ox, zto
%Compared with Experimental Example 1, by performing hydrogen circulation, the same amount of raw material synthesis gas was processed by the same reactor,
It can be seen that there is an effect of improving the conversion rate of about 10-carbon monoxide.

[Experiment example S]

In fact, a reaction test using the same catalyst and reaction apparatus as in Experimental Example 2 was conducted at a hydrogen/carbon monoxide molar ratio of 2.0 at the inlet of the reaction tube and a reaction pressure of 40 Yu/ctt? G, gas space velocity G111
The reaction was carried out under the reaction conditions of 8V -LOOOh-" (based on the inlet gas amount), and the following intermediate product was obtained.

Conversion rate of carbon monoxide 9 & 5 thi intermediate product composition (molti) Dimethyl ether IZ8 thiic acid carbon 2.1% hydrogen
5a8chi horse Q, OR, O
E[,co,,CI! , 24. S [Example 1] The intermediate product of Experimental Example 3 was fed to a fluidized bed reactor and the gas hourly space velocity GHE? V -6y h-1 (based on dimethyl ether supply amount), reaction temperature 400°C, reaction pressure 5ψ'dG
It was brought into contact with the following crystalline silicate catalyst under the following reaction conditions.

The crystalline silicate used here was manufactured as follows.

Water glass, lanthanum chloride, water, 56MatO・La,
O, .80 Sin, @1600 H, O was prepared in a molar ratio, and an appropriate amount of hydrochloric acid was added to the mixture so that the pH of the mixture was around 9, and tri-n propyl was added as an organic compound. LL! amine, n-propyl bromide and methyl ethyl ketone! LtO.

20 times the number of moles was added, mixed well, and placed in a 1/2 stainless steel autoclave. The above mixture was heated to about 50 Or
The reaction was carried out at 100° C. for 1 day and then at 170° C. for 38 hours while stirring at pm. After cooling, the solid content was filtered, thoroughly washed with water until the pH of the washing water became about 8, dried at 110°C for 12 hours, and calcined at 550°C for about 3 hours. The crystal grain size of this product is about 1μ, and the composition after removing organic compounds is expressed in dehydrated form as 14Nζ0-La,O,・80
It was 810. This is called crystalline silicate 1.

Further, when preparing the raw materials for crystalline silicate 1, the same operation was performed except that cerium chloride was added in a ratio of 15 mol to 0.5 mol in addition to lanthanum chloride, and α4NI! L! O・
(α5L&!O, -α5CJe, 03) -80SiO
A crystalline silicate 2 having a composition of , was prepared.

Next, 1N crystalline silicate 2 synthesized as follows.
It was immersed in hydrochloric acid and treated at 80°C for 7 days. After washing the fish with ion-exchanged water until the pH of the washing water becomes 6,
It was dried at 0° C. for 12 hours to obtain hydrogen ion type crystalline silicate.

Next, an equal amount of alumina boehmite dry gel powder was added as Aj, 03 to the latter crystalline silicate and mixed well, and after gradually adding 54 HMO solution, it was molded into a size of t 5 mφ using an extruder. , this at 110℃
The catalyst was dried for 12 hours and calcined at 550°C for S hours, and this was used as a catalyst for the second stage reaction.

As a result, the following product product was obtained.

Conversion rate of dimethyl ether 9a6% Product composition (wt) C040! 57chi037.5% 0, 15.4%C5+69
．． 4 H [Effect of the invention] In a two-step synthesis method for synthesizing gasoline from synthesis gas via dimethyl ether, hydrogen is separated from the first stage dimethyl ether synthesis reaction product and recycled to the raw material synthesis gas, thereby improving the synthesis gas. Gas can be efficiently converted to dimethyl ether and gasoline yield can be increased. This is particularly effective when the feedstock synthesis gas has a low hydrogen/carbon monoxide ratio.

[Brief explanation of the drawing]

FIG. 1 shows a 70-sheet for producing gasoline from syngas in accordance with one embodiment of the present invention.

Claims (1)

[Claims] In a two-step method for synthesizing liquid hydrocarbons (gasoline) from synthesis gas consisting of a mixture of carbon monoxide and hydrogen via dimethyl ether, the first step is to convert the synthesis gas into methanol synthesis catalyst and acid form. Contact with a catalyst consisting of a mixture of dehydration catalysts at elevated temperatures of up to 400° C. separates hydrogen from the reaction product consisting primarily of dimethyl ether and circulates it to the feed synthesis gas, increasing the hydrogen/carbon monoxide ratio from the feed synthesis gas. The second step is to increase the dimethyl ether conversion of the synthesis gas, and the second step converts the dimethyl ether in its dehydrated form to oxide molar ratio: (1.0±0.4)R_2/nO·[aLa_2O_3
・bCe_2O_3・cM_2O_3]・ySiO_2
In the above formula, R; one or more monovalent or divalent cations n; valence M of R; one or more trivalent transition metal ions and/or aluminum ions a+b+c=1 a≧0 A synthesis gas characterized in that it is brought into contact with a crystalline silicate catalyst having a chemical composition of b≧0 c≧0 a+b>0 y≧12 at a high temperature of up to 500° C. to produce an organic product containing aromatic hydrocarbons. A method for converting into aromatic hydrocarbons.